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Results for “Laser Scanning Cytometry”

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PubMed2006

Effect and mechanism of epidermal growth factor on proliferation of GL15 gliomas cell line.

The effects of epidermal growth factor (EGF) on proliferation of G15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells were treated with EGF at different concentrations, cell count method was used to determine the proliferation of glioma cells, cell cycle and apoptosis were analyzed by flow cytometry (FCM), and laser scan confocal microscope (LSCM) was used to measure the cytoplasmic free calcium. The results showed that GFAP was diffusedly expressed in GL15 cells and EGFR was over-expressed. EGF at doses of < or =1 ng/mL could significantly stimulate cell proliferation, cells in phase G0/G1 decreased, and those in phase S increased. EGF at doses of 10 and 100 ng/ml could inhibit the cell proliferation significantly, and the apoptosis ratio in high dose of EGF group was higher than in control group. EGF could significantly induce a quick rise of intracellular free calcium, but the peak value of intracellular free calcium activated by high dose of EGF was higher than by low dose of EGF. It was suggested that EGF had a dual effect on gliomas: low dose of EGF could stimulate the cell proliferation of gliomas, but high dose of EGF could induce the cell apoptosis and inhibit the proliferation of gliomas, which might be contributed to the difference of intracellular free calcium.

Apoptosis↗

PubMed2006

In vitro assessment of transferrin-conjugated liposomes as drug delivery systems for inhalation therapy of lung cancer.

Most human tumours over-express receptors for growth factors and peptide hormones, which are being increasingly studied as a means to selectively deliver cytotoxic agents. An example being the transferrin receptor (TfR, CD71). Here, we studied expression levels and location of TfR in different lung epithelial cell types (i.e., bronchial and alveolar epithelial cells) by flow-cytometry and confocal laser scanning microscopy (CLSM). Furthermore, we assessed uptake levels and cytotoxicity of transferrin (Tf)-conjugated liposomes in vitro. TfR was found to be expressed at a significantly higher level in bronchial epithelial cells compared with their alveolar counterparts. Cells of cancerous origin (i.e., A549 cell line) showed a higher TfR expression level than healthy alveolar epithelial type II cells in primary culture. CLSM revealed TfR to be located primarily at the basolateral aspect of cells, with the exception of cells undergoing mitotic proliferation, which also showed TfR at their apical membranes, due to their loss of cell polarity. Higher expression levels of TfR correlated well with enhanced uptake of Tf-liposomes and increased levels of cytotoxicity. Liposome uptake was temperature-dependent and inhibitable by excess free Tf. Tf-conjugated liposomes appear as good candidates for an approach to deliver cytostatic drugs to sites of lung cancer by inhalation.

Antineoplastic Agents↗

PubMed2001

Specific ligands of the peripheral benzodiazepine receptor induce apoptosis and cell cycle arrest in human colorectal cancer cells.

The peripheral benzodiazepine receptor (PBR) has been implicated in growth control of various tumour models. Although colorectal cancers were found to overexpress PBR, the functional role of PBR in colorectal cancer growth has not been addressed to date. Using primary cell cultures of human colorectal cancers and the human colorectal carcinoma cell lines HT29, LS174T, and Colo320 DM we studied the involvement of PBR in the growth control and apoptosis of colorectal cancers. Both mRNA and protein expression of PBR were detected by RT-PCR and flow cytometry. Using confocal laser scanning microscopy and immunohistochemistry the PBR was localized in the mitochondria. The specific PBR ligands FGIN-1-27, PK 11195, or Ro5-4864 inhibited cell proliferation dose-dependently. FGIN-1-27 decreased the mitochondrial membrane potential, which indicates an early event in apoptosis. Furthermore, FGIN-1-27, PK 11195 or Ro5-4864 increased caspase-3 activity. In addition to their apoptosis-inducing effects, PBR ligands induced cell cycle arrest in the G(1)/G(0)-phase. Thus, our data demonstrate a functional involvement of PBR in colorectal cancer growth and qualify the PBR as a possible target for innovative therapeutic approaches in colorectal cancer.

Adult↗

PubMed2000

Chemical and physiological characterization of fluo-4 Ca(2+)-indicator dyes.

We have developed fluo-4, a new fluorescent dye for quantifying cellular Ca2+ concentrations in the 100 nM to 1 microM range. Fluo-4 is similar in structure and spectral properties to the widely used fluorescent Ca(2+)-indicator dye, fluo-3, but it has certain advantages over fluo-3. Due to its greater absorption near 488 nm, fluo-4 offers substantially brighter fluorescence emission when used with excitation by argon-ion laser or other sources in conjunction with the standard fluorescein filter set. In vitro, fluo-4 exhibited high fluorescence emission, a high rate of cell permeation, and a large dynamic range for reporting [Ca2+] around a Kd(Ca2+) of 345 nM. We have also developed several Ca(2+)-indicators related to fluo-4 having lower affinities for Ca2+ that are useful in cellular studies requiring quantification of higher [Ca2+]. In a variety of physiological studies of live cells, fluo-4 labeled cells more brightly than did fluo-3, when challenged with procedures designed to elevate calcium levels. Fluo-4 is well suited for photometric and imaging applications that make use of confocal laser scanning microscopy, flow cytometry, or spectrofluorometry, or in fluorometric high-throughput microplate screening assays. Because of its higher fluorescence emission intensity, fluo-4 can be used at lower intracellular concentrations, making its use a less invasive practice.

3T3 Cells↗

PubMed2005

Expression of membrane-bound IL-15 by bone marrow fibroblast-like stromal cells in aplastic anemia.

In order to explore the relationship between IL-15 and aplastic anemia (AA), bone marrow (BM) fibroblast-like stromal cells (BMFSCs) were obtained from BM samples of 23 AA patients by density centrifugation and primary culturing in vitro. Indirect immunofluorescence labeling as well as flow cytometry and confocal laser scanning microscopy analysis were used to determine the expression of membrane-bound IL-15 (mIL-15) on the surface of BMFSCs derived from AA patients (AA-BMFSCs). The effects of IFN-gamma and cyclosporin A (CsA) on the expression of mIL-15 were also investigated. [(3)H]thymidine incorporation test as well as specific antibody inhibition and Transwell separation experiment was adopted to functionally evaluate the expression of mIL-15 on the surface of AA-BMFSCs. mIL-15 was found to be over-expressed on the surface of AA-BMFSCs. IFN-gamma further significantly up-regulated its expression, which, however, was inhibited by CsA. Interestingly, a tight correlation was found between the expression of mIL-15 and IL-15Ralpha on the surface of AA-BMFSCs. AA-BMFSCs had the capability to stimulate the proliferation of T lymphocytes, which was partly or completely inhibited by using neutralizing anti-IL-15Ralpha antibody, neutralizing anti-IL-15 antibody, blocking anti-IL-2/15Rgamma(c) mAb or Transwell chambers with a 0.3-mum pore size membrane to block the direct cell-to-cell contact between AA-BMFSCs and T cells. Apparently, BMFSCs as the most important component of BM hematopoietic microenvironment usually over-express mIL-15 in AA patients. Therefore, AA-BMFSCs may indirectly participate in the T cell-mediated destruction of hematopoietic progenitors in AA by recruiting T cells to BM and stimulating them in situ.

Adolescent↗

PubMed2006

Yersinia enterocolitica YopP inhibits MAP kinase-mediated antigen uptake in dendritic cells.

Yersinia enterocolitica (Ye) targets mouse dendritic cells (DCs) and inhibits their ability to trigger T cell activation. Here we have investigated whether Ye might interfere with antigen presentation in DCs. Infection of DCs with the Ye wild-type strain reduced OVA uptake by DCs as demonstrated by flow cytometry and confocal laser scan microscopy. In contrast, DCs infected with Yersinia outer protein P (YopP)-deficient mutant strain rapidly internalized OVA. Furthermore, transfection of DCs with YopP, but not with a cysteine protease deficient YopP-C172A mutant, reduced uptake of OVA. This finding suggests that YopP, a virulence factor of Ye, inhibits OVA uptake by DCs. By the use of MAPK inhibitors we provide evidence that YopP mediates reduction of OVA uptake by its ability to block MAPK signalling pathways in host cells. Using transferrin (Tf) as specific marker for clathrin-mediated endocytosis (CME) and lucifer yellow (LY) as specific marker for macropinocytosis (MP) we could show that YopP inhibits CME, whereas other Yops inhibit MP. In keeping with these data, activation and proliferation of OVA-specific T cells was reduced when DCs were treated with MAPK inhibitors. Together, our data demonstrate that (i) MAPK play an important role in antigen uptake by CME in DCs, and (ii) that YopP inhibits this pathway of antigen uptake in DCs, which might contribute to evasion of adaptive immunity.

Animals↗

PubMedDate not supplied

Syndecan-1-dependent homotypic cell adhesion in HT58 lymphoma cells.

OBJECTIVES: Many cellular functions are controlled by cell-cell and cell-matrix interactions. It has recently been found that syndecans, transmembrane heparan sulphate (HS) proteoglycans, can act as receptors or co-receptors and modulate cell adhesion. Our aim was to study the role of syndecan-1 in the aggregation of human lymphoma cells, and to investigate its effect on cell survival. METHODS: Immunocytochemistry, confocal laser scanning microscopy, flow cytometry and aggregation/reaggregation bio-assays were used on HT58, BL41/95 and Raji lymphoma cell lines. RESULTS: Bio-assays showed that the aggregation of HT58 cells was inhibited by heparin, HS, removal of the HS chain and binding of the anti-syndecan-1 monoclonal antibody. In the search for a counter-receptor of syndecan-1, several adhesion molecules were tested, but none of them proved to be the adhesion partner. In the case of heparitinase/trypsin digestion with long-term inhibition of HS synthesis (sodium chlorate treatment), the inhibited aggregation was accompanied by cell cycle arrest and the induction of apoptosis. CONCLUSIONS: The results obtained showed that surface syndecan-1 expression contributes to homotypic adhesion. In addition, HS chains, including those on syndecan-1, take part in the regulation of cell proliferation and active cell death in HT58 lymphoma cells.

Apoptosis↗

PubMedDate not supplied

Retinal pigment epithelial phagocytosis and metabolism differ from those of macrophages.

The purpose of this study is to compare primary human retinal pigment epithelium (RPE) cells with respect to particle uptake and further processing steps with immunological phagocytes for a better understanding of the possible role of RPE cells in triggering autoimmune diseases in the eye. We investigated the similarities of human RPE and monocytes/macrophages studying the uptake of fluorescein- and europium-labeled synthetic microparticles and microbial pathogens by human and bovine RPE cultures and a permanent RPE cell line (CRL). The uptake was monitored by laser scanning microscopy, flow cytometry and time-resolved fluorescence analysis; for comparison, macrophages and a macrophage-like cell line (MonoMac6) were used. A size-dependent uptake was seen in primary RPE cultures as well as in CRL, showing a preferential uptake of smaller beads followed by Staphylococcus aureus and Escherichia coli. Opsonization with serum caused a modest increase in bacteria uptake, but in contrast to macrophages, the classical complement receptors were not found on RPE cells. Living bacteria were also ingested in a time-dependent manner, but, as no intracellular overgrowth was observed, we further investigated the oxidative ability of RPE as a possible mechanism for microbial suppression. Unlike macrophages/granulocytes, no respiratory burst was detected in RPE cells, but, comparable to MonoMac6, IFN-gamma induced neopterin in the human RPE. Interestingly a diurnal rhythm of phagocytosis was observed which was influenced by light exposure suggesting that RPE cells maintain their circadian rhythm also in cell culture to a certain extent. This study further demonstrates that in addition to similar phagocytic properties the RPE still shows substantial metabolic differences in comparison to blood-derived phagocytes.

Animals↗

PubMed1999

[Merocyanine 540-mediated photodynamic therapy inhibits P-glycoprotein (P-gp) activity in adriamycin-resistant K562 cells].

The photosensitizing dye merocyanine 540 (MC540) has been used in preclinical models and in a phase I clinical trial in the U.S.A. for the extracorporeal purging of autologous bone marrow grafts contaminated with leukemia or lymphoma. In this communication, we report MC540-mediated photodynamic therapy (PDT) was effective in purging leukemic cells expressing P-gp. When K562 and K562/ADM were exposed to MC540 (15 micrograms/ml) and white light (145.8 kJ/m2), the concentration of K562 and K 562/ADR was reduced by 1.8 and 3.0 log, respectively. Using flow cytometry and confocal laser scan microscopy, MC540 and calcein-AM were bound intracellularly and effluxed by P-gp in K562/ADM. In K562/ADM, calcein-AM efflux was inhibited by P-gp modulator, cyclosporin A (5 microM) and verapamil (15 micrograms/ml). In contrast, MC540 efflux was inhibited by cyclosporin A but not verapamil. Furthermore, MC540-mediated PDT inhibited efflux of calcein-AM and MC540, and induced the accumulation of dyes in K562/ADM. We conclude that MC540 is a substrate of P-gp and that MC540-mediated PDT is useful for purging MDR cells through inhibition of P-gp activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Apoptosis occurs in isolated and banked primary mouse hepatocytes.

Isolation and cryopreservation of freshly isolated hepatocytes is considered a standard procedure for the long-term storage of liver cells. However, most existing methods for banking hepatocytes do not allow sufficient recovery of viable cells to meet the needs of basic research or clinical trials of hepatocyte transplantation. The mechanisms underlying this poor rate of hepatocyte recovery are unknown. Although much of the cellular damage in freezing is caused by formation of ice crystals within the cells, this is largely prevented by the use of dimethyl sulfoxide (DMSO) and controlled rate freezing. As we demonstrated recently, necrosis does occur in primary hepatocytes following isolation and cryopreservation. In the present study, we explored the contribution of apoptosis, another form of cell death, in primary hepatocytes banked for transplantation. We evaluated apoptosis of C57BL/6J mouse primary hepatocytes using several different methods. Annexin binding and the TUNEL assay, in conjunction with flow cytometry and confocal laser scanning microscopy, revealed that the percentage of apoptotic cells was dramatically elevated in cryopreserved cells compared with that in the control group of unfrozen cells. DNA laddering detected by DNA electrophoresis in agarose gel also supported the presence of apoptosis in isolated and banked liver cells. Moreover, we found that the addition of glucose (from 10 to 20 mM) into the freezing solution (University of Wisconsin Solution) decreased the rate of apoptosis by 84% and improved the cell attachment at least fourfold in cryopreserved cells. These results suggest that apoptosis might contribute to cell death in isolated and banked primary hepatocytes.

Animals↗

PubMed2001

[Involvement of mitochondrial membrane potential in the homoharringtonine induced apoptosis of leukemic T-cells].

OBJECTIVE: Investigation of the role of mitochondrial membrane potential (MMP) in the homoharringtonine (HHT)-induced apoptosis. METHODS: Annexin V staining, flow cytometry and confocal laser scan microscopy were used to observe the relationship between Bax, cytochrome C and MMP in the HHT-induced apoptosis of leukemic T lymphocytic line Molt-3. RESULTS: The induction of apoptosis by HHT resulted in the translocation of Bax from cytosol to mitochondrial membrane and the decrease of cellular MMP, followed by the release of cytochrome C from mitochondria to cytosol. CONCLUSIONS: Changes of mitochondrial membrane potential might play a critical role in the HHT-induced apoptosis of leukemic T-cells.

Apoptosis↗

PubMed2001

[Studies on the anti-tumorpromotion activities of dehydroepiandrosterone and its mechanism of action].

AIM: To investigate the anti-tumorpromoting activity of dehydroepiandrosterone (DHEA) and its mechanism of action. METHODS: Using croton oil-induced ear edema model and applying confocal laser scanning microscopy, flow cytometry, immuno-fluorescent techniques to investigate the inhibitory effect of DHEA on tumor promotion. RESULTS: DHEA 25 mg.kg-1 was shown to inhibit croton oil induced ear edema in mice by 51%. DHEA at dose of 40 mg.kg-1 and 10 mg.kg-1 exhibited inhibitory effects on croton oil-induced ornithine decarboxylase (ODC) activity by 64% and 53%, respectively. These results revealed that DHEA can block the change of cell cycle and the percentage of S phase was decreased to 17% at concentration of 10(-7) mol.L-1. The increase of[Ca2+]i and pH as well as PKC-activation induced by TPA stimulation were significantly inhibited by DHEA pretreatment. CONCLUSION: The present experiments demonstrate that DHEA appears to be an attractive candidate as an anti-tumorpromotion agent for tumor chemoprevention. The mechanism of its action might be related to its inhibitory effects on ODC activity and Ca(2+)-DG-PKC signal pathway.

Animals↗

PubMed2005

[PTEN induces anoikis through its phosphatase activity in hepatocellular carcinoma cells].

OBJECTIVE: To investigate the effect and mechanisms of tumor suppressor gene PTEN on the induction of anoikis of hepatocellular carcinoma SMMC-7721 cells. METHODS: SMMC-7721 cells were transfected with GFP plasmids containing wild-type PTEN or phosphatase inactivating mutant PTEN (C124A-PTEN) in vitro; The PTEN expression and the phosphorylation levels of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) were detected by Western blotting; Flow cytometry assay and laser scanning confocal microscopy were used to analyze apoptosis in adherent and non-adherent cells. RESULTS: Compared with the control, PTEN expression in the cells transfected with wild-type PTEN increased to 248%, while the phosphorylation level of FAK and Akt decreased 65.2% and 89.1%, respectively; and the anoikis percentage increased from 9.5% to 31.3%. In the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the anoikis percentage had obviously changed, although the PTEN expression enhanced dramatically in comparison with the control. CONCLUSION: Through its phosphatase activity, tumor suppressor gene PTEN can suppress the phosphorylation of FAK and Akt, and induce anoikis in hepatocellular carcinoma cells.

Anoikis↗

PubMed2005

[Reversal of multidrug resistance of HL-60 adriamycin resistant leukemia cell line by quercetin and its mechanisms].

OBJECTIVE: Quercetin, a widely distributed natural flavonoid with a variety of biological functions, can reverse multidrug resistance (MDR) in leukemia according to recent researches. The aim of this study was to investigate the mechanisms of reversal of multi-drug resistance by quercetin mainly in respect of membrane transporters. METHODS: MTT cell viability assay was used to verify the chemo-sensitization to daunorubicin (DNR) by quercetin in HL-60/ADM cell line and determine the effective reversal concentration, the expression of MRP(1) gene and its protein product, multidrug resistant associated protein 1 by RT-PCR and flow cytometry By confocal laser scanning microscopy, the subcellular distribution of DNR in HL-60/S and HL-60/ADM cells was examined before and after quercetin exposure. RESULTS: Compared with HL-60/S, 20-40 micromol/L quercetin in vitro remarkably enhanced the sensitivity of HL-60/ADM cells to daunorubicin, down-regulated the expression of MRP(1) gene and its protein product MRP(1), restored the abnormal subcellular distribution of daunorubicin, so as to reverse MDR. Moreover, such an effective concentration of quercetin was non-toxic to the cells. CONCLUSION: Quercetin could be a candidate of effective multidrug resistance-reversing agent with low toxicity in leukemia chemotherapy.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2004

[Controlled live dendritic cell vaccine mediates potent antitumor immune responses].

OBJECTIVE: To investigate the efficiency of antitumor immune responses induced by a controlled live dendritic cell (DC) vaccine. METHODS: DC precursors were isolated from Fischer 344 rat bone marrow and cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4. The rat ovarian tumor cell line NuTu-19 was genetically modified by retroviral-mediated suicide gene (HSV(1)-TK), and the positive clones were selected using G418. Live DC vaccine was then fused with DC and NuTu-19/TK cell by polyethylene glycol. The characteristics of live DC vaccine were assayed with flow cytometry and confocal laser scanning microscopy. The specific expression of HSV(1)-TK gene in live DC vaccine was evaluated by RT-PCR and western blot. The sensitivity of live DC vaccine to ganciclovir (GCV) was evaluated by methylthiazoletetrazolium assay. In vivo, rats vaccinated twice with live DC vaccine were compared to those vaccinated with killed DC vaccine, unfused DC and NuTu-19/TK cell or phosphate buffered saline. Seven days following the last immunization, the rats were sacrificed to test the specific cytotoxic T lymphocyte (CTL) activity by lactate dehydrogenase release assay, or challenged with NuTu-19 and tumor incidence was observed. RESULTS: The fusion efficiency was approximately (23 +/- 14). Live DC vaccine displayed an up-regulated expression of major histocompatibility complex (MHC)-IIOX6 (87.6 +/- 3.4)%, costimulatory molecule B(1 - 2) (71.1 +/- 9.3)%, integrin OX 62 (68.0 +/- 7.4)%, and adhesion ICAM-1 (77.1 +/- 2.0)%, and specifically expressed HSV(1)-TK gene. Our data showed that spleen T lymphocytes from rats vaccinated with live vaccine displayed enhanced CTL activity (61.8 +/- 8.3)% contrast to that of rats vaccinated with killed vaccines (26.0 +/- 3.8)% (P < 0.05). Compared to the control groups, rats immunized with live DC vaccine demonstrated a significant delay in tumor development [(39 +/- 8) d vs (70 +/- 16) d], reduced tumor incidence (100% vs 80%) and decreased tumor volume [(806 +/- 553) mm(3) vs (89 +/- 53) mm(3), P < 0.05]. Seventy-three percent of TK-transduced live DC vaccine was killed after 7 of GCV treatment by a functional assay. CONCLUSION: The results demonstrate that DC live vaccine modified by HSV(1)-TK gene can induce efficient protective immunity and be killed by GCV.

Animals↗

PubMed1997

Solid phase cytometry for detection of rare events.

We describe a simple and rapid laser scanning device for solid phase cytometry. This system can detect and count fluorescent cells over a 22 mm diameter surface (membrane or glass circle) as well as quantify the fluorescence that they emit. A comprehensive discrimination package includes optical and software parameters and accurately distinguishes between valid signals (e.g., labelled cells) and nonspecific signals (e.g., auto-fluorescent particles and debris). Any event detected may also be easily confirmed by visual observation after transfer of the sample to an epifluorescence microscope fitted with a motorized stage driven by the system. We show a linear relationship between the amount of fluorescein coupled to the cells and the fluorescence signal of the cells detected. This approach is not destructive and further characterization of the sample may be carried out. We have been able to detect rare cellular events at a frequency of 10(-7) in 3 min. Potential applications include monitoring of residual disease in oncology and detection of virus-infected cells circulating at very low frequencies.

Animals↗

PubMed1994

[Study on the fertility of epididymal sperms].

One approach to the treatment of obstructive azoospermic cases in whom either vasovasostomy cannot be performed or the vas deferens is absent is to construct an artificial spermatocele in the epididymis. By using this method to recover sperms for use in AIH, we have succeeded in achieving pregnancy in only 2 of 35 cases, leading us to investigate the fertility of the recovered sperms. Sperm fertility was investigated by the hypoosmotic swelling (HOS) test, observation by confocal laser-scanning microscope (CLSM), flow cytometry and hamster egg sperm penetration test. The percentage of swollen sperm determined by the HOS test was 15.0-83.3%, with a mean of 47.6 +/- 16.1%, significantly lower than the values of the normal group and the infertile male group, excluding cases of obstructed azoospermia. Examination by confocal laser-scanning microscope of samples stained with PI and FITC-PSA or PI and FITC-Con A stain revealed viable and dead spermatozoa as well as viable and dead acrosome-reacted spermatozoa. In addition, fertility was evaluated from the distribution of spermatozoa in each area from the flow cytometry percentage. This method was shown previously to be useful for the evaluation of fertility as it demonstrated the presence of numerous spermatozoa in the fertile area of cases who did not succeeded in pregnancy. The hamster egg sperm penetration test yielded a fertility rate of 0-25% with a mean of 8.2 +/- 10.0%, which was significantly lower than the value of the normal group, but was not significantly different from the infertile group. The findings of this study indicated that the fertility of epididymal sperms is low, thereby pointing to the need for studies to improve the materials used in the artificial spermatocele as well as the method of sperm recovery. Furthermore, our findings suggest that flow cytometry may be used to select the epididymal sperms with the highest fertility for sperm recovery.

Animals↗

PubMed2003

Composite lipid polyelectrolyte capsules templated on red blood cells: fabrication and structural characterisation.

Charged phospholipids and mixtures of charged phospholipids with zwitterionic lipids were adsorbed onto polyelectrolyte capsules templated on erythrocytes. The assembly was proved by means of electrophoretic mobility measurements, confocal laser scanning microscopy and flow cytometry. Freeze-fracture electron microscopy proved that the phospholipids assemble as bilayers or multilayers. Single particle light scattering showed that bilayers composed of anionic lipids can be intercalated between subsequent polyelectrolyte inter-layers in a regular manner. Neutral lipids can form multilayers. A pronounced decrease in capsule permeability for small polar dyes upon lipid adsorption was followed by confocal laser scanning microscopy.

Adsorption↗