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David Juncker

Publications and source records attributed to David Juncker.

3 recordsLinked to original sources
PubMed2026

Biomimetic Hydrogels with Nucleus Pulposus-like Viscoelasticity and ECM Peptides for Discogenic Differentiation of Stem Cells.

Intervertebral disc (IVD) degeneration is a leading cause of low back pain (LBP), primarily originating in the nucleus pulposus (NP). Regenerative strategies combining mesenchymal stem cells (MSCs) with biomaterials offer great potential for NP repair by replenishing cells and restoring extracellular matrix (ECM). However, key translational challenges remain, including limited stem cell differentiation, poor cell survival in the harsh degenerative niche, and insufficient biomaterial support. While matrix viscoelasticity has been shown to influence adipose-derived stem cell (ASC) discogenic differentiation, its interplay with cell-adhesive ligands for IVD regeneration remains unclear. Moreover, most current hydrogels fail to replicate the ultrafast stress relaxation properties of native non-degenerative human NP tissue. Here, we developed viscoelastic ECM peptide-functionalized hydrogels (VEPH), specifically designed to mimic healthy human NP biomechanics and promote ASC differentiation for NP regeneration. We biochemically conjugated NP ECM-derived adhesive peptides (IKVAV, hA5G26, CHAD) through maleimide-thiol click chemistry, achieving hydrogels with significantly faster stress relaxation (∼25 s) compared to conventional viscoelastic alginate hydrogels (>100 s). Our results demonstrated that VEPH supported >95% ASC viability and robust metabolic activity over 21 days in 3D culture. Notably, the IKVAV-functionalized hydrogel significantly enhanced ASC cell-matrix interactions, upregulated NP marker expression (KRT18, HIF-1α, ITGA3, and CD24), and promoted type-II collagen secretion, indicating an NP-committed cell fate. Our findings highlight the synergistic roles of matrix viscoelasticity and NP-specific biochemical cues in directing ASC discogenic differentiation and advancing novel biomaterial design for IVD regeneration.

cell-adhesive peptides↗
PubMed2002

Autonomous microfluidic capillary system.

The transport of minute amounts of liquids using microfluidic systems has opened avenues for higher throughput and parallelization of miniaturized bio/chemical processes combined with a great economy of reagents. In this report, we present a microfluidic capillary system (CS) that autonomously transports aliquots of different liquids in sequence: liquids pipetted into the service port of the CS flow unidirectionally through the various sections of the CS, which comprises a 15-pL reaction chamber, into the capillary pump. A CS can thus be operated by simply delivering the different samples to its service port. The liquid transport concept presented here is advantageous because the pumping and valving functions are integrated into the device by means of capillary phenomena, and it therefore does not require any external power supply or control device. Thus, arrays of CSs can easily be formed by cloning a functional CS. Alternatively, the flow of liquids in CSs can also be interactively tuned if desired by (i) forcing the evaporating of liquid out of the capillary pumps and (ii) by contacting a secondary, removable capillary pump to the embedded ones. We illustrate the possibilities of CSs by conducting a surface immunoassay for a cardiac marker, within 25 min, on an area of 100 x 100 microm2, using 16 sequential filling steps.

Journal Article↗