Microstencils for the patterning of nontraditional materials.

Rohit Pal; Kyung Eun Sung; Mark A Burns

doi:10.1021/la052811s

Home/Archive/PubMed

PubMed · 16732668

Microstencils for the patterning of nontraditional materials.

Rohit Pal·Kyung Eun Sung·Mark A Burns

View original source ↗Export metadata ↓

Abstract

A microfabrication technique that uses a photolithographically patterned film as a microstencil has been developed. This microstencil has a bilayer structure comprised of parylene and SU-8 films with thicknesses from 4 to 100 microm. The parylene layer enables the microstencil to be mechanically peeled from hydrophilic substrates. Since no chemicals are required to release the microstencil, this technique can be used to pattern chemically and biologically sensitive materials. The amount of material deposited can be automatically controlled by the height of the SU-8 structures or externally controlled by spin coating or other thin film deposition techniques. This patterning method is very versatile and has been used to pattern features as small as 25 by 25 microm on silicon, glass, and polymer substrates. As an initial demonstration, we have patterned wax, cells, proteins, sol, and CYTOP.

Explore related subjects

Coated Materials, Biocompatible Microfluidic Analytical Techniques Journal Article Research Support, N.I.H., Extramural

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Rohit Pal, Kyung Eun Sung, Mark A Burns. 2006-06-06. Microstencils for the patterning of nontraditional materials.. https://doi.org/10.1021/la052811s

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Modeling of degradation and drug release from a biodegradable stent coating.

Biodegradable polymeric coatings on cardiovascular stents can be used for local delivery of therapeutic agents to diseased coronary arteries after stenting procedures. This can minimize the occurrence of clinically adverse events such as restenosis after stent implantation. A validated mathematical model can be a very important tool in the design and development of such coatings for drug delivery. The model should incorporate the important physicochemical processes responsible for the polymer degradation and drug release. Such a model can be used to study the effect of different coating parameters and configurations on the degradation and the release of the drug from the coating. In this paper, a simultaneous transport-reaction model predicting the degradation and release of the drug Everolimus from a polylactic acid (PLA) based stent coating is presented. The model has been validated using in vitro testing data and was further used to evaluate the influence of various parameters such as partitioning coefficient of water, autocatalytic effect of the lactic acid and structural change of the matrix, on the PLA degradation and drug release. The model can be used as a tool for predicting drug delivery from other coating configurations designed using the same polymer-drug combination. In addition, this modeling methodology has broader applications and can be used to develop mathematical models for predicting the degradation and drug release kinetics for other polymeric drug delivery systems.

Coated Materials, Biocompatible↗

PubMed2007

Effectiveness and safety of the sirolimus-eluting stents coated with bioabsorbable polymer coating in human coronary arteries.

BACKGROUND: Although the sirolimus-eluting stent (CYPHER, Cordis, USA) has shown a dramatic reduction of restenosis, there are still some concerns about its efficacy and safety. Its durable polymer coating may enhance neointimal proliferation and residual sirolimus, which cannot be released from polymer, may result in incomplete reendothelization. As a drug reservoir, bioabsorbable polymer (polylactic acid, PLA) is more rational. OBJECTIVE: We aimed to determine the safety and efficacy of sirolimus-eluting stent coated with PLA (EXCEL, JW Medical Systems, China) in the treatment of human coronary arterial diseases. METHODS: The study included 31 patients with de novo coronary lesions, with vessels 2.5-3.5 mm in diameter. The primary end points included the percentage of in-stent restenosis of the luminal diameter and in-stent late luminal loss at 6 months, as determined by quantitative angiography. The secondary end point was the major adverse cardiac events (MACE) 30 days and 6 months after the index procedure. RESULTS: Forty-eight EXCEL stents were successfully delivered in the 34 lesions, and multiple stents were implanted in 35.3% of lesions. All patients were discharged without clinical complications and completed clinical follow-up at 1 and 6 months. No MACE had occurred. Twenty patients (30 stents) completed 6 months of angiographic follow-up. No in-stent or in-lesion restenosis (diameter stenosis > or =50%) was observed. In-stent late loss was (0.07 +/- 0.17) mm. CONCLUSIONS: The implantation of EXCEL stent is feasible and safe and elicits minimal neointimal proliferation. This new stent has potential advantages regarding the long-long-term result over the commercially stent as the new stent has no sustained stimulation to the local tissue.

Coated Materials, Biocompatible↗

PubMed2007

Thermal-mechanical study of functionally graded dental implants with the finite element method.

This article investigates the thermal-mechanical performance of hydroxyapatite/titanium (HA/Ti) functionally graded (FG) dental implants with the three-dimensional finite element method. The stresses induced by occlusal force for the present HA/Ti FG implant are calculated to compare with the corresponding stresses for the titanium dental implant. Thermal-mechanical effect of temperature variation due to daily oral activity is also studied. The HA/Ti FG dental implant performance is evaluated against the maximum von Mises stress, which is the general performance indicator, the first principal/tensile stress for mechanical failure of implant-bone-bond and the third principal/compressive stress for bone absorption. Simulation results indicate that under the influence of occlusal force only, the FG implants with different HA fraction along the implant length perform almost equally well, while the titanium implant sustains much higher von Mises stress. However, when thermal stress is also considered, the FG implant having HA fraction exponential index of m = 2 with temperature decrease of 20 degrees C yields the highest first principal and von Mises stresses among all the FG and titanium implants.

Coated Materials, Biocompatible↗