Biology subjects

Maleckis, K.

Publications and source records attributed to Maleckis, K..

3 recordsLinked to original sources

bioRxiv2026

Heparinized Elastomeric Nanofibrillar Grafts: A Novel Approach for Mechanically Tunable, Cell-Supportive, and Thromboresistant Vascular Substitutes

The clinical success of vascular grafts relies on three main prerequisites: artery-tuned mechanics, cell-supportive microstructure, and a thromboresistant interface. Most current solutions address only a subset of this triad and equate mechanical matching with compliance alone, which can lead to disturbed hemodynamics, maladaptive mechanobiology, and adverse graft-host biochemical interactions that frequently culminate in clinical complications and graft failure. This study presents polyurethane-based heparin-functionalized elastomeric nanofibrillar grafts (H-ENGs) that integrate all three prerequisites while allowing multi-parameter mechanical mimicry. To address the principal failure mode of early thrombosis, a small fraction of polyethyleneimine (PEI) is added to the ENG electrospinning solution to form P-ENGs, enabling one-step covalent heparin conjugation to form H-ENGs. The decoupled design of the ENG platform preserves the biomimetic microstructure and mechanics following PEI incorporation and heparinization, enabling adaptable, indication-specific optimization. In vitro, H-ENGs exhibit good cytocompatibility with minimal hemolysis, platelet adhesion, and whole blood clotting. Pilot porcine abdominal aorta interposition studies demonstrate feasibility: H-ENGs exhibit favorable surgical handling, intact suture-line integrity, and anastomotic hemostasis under dynamic flow, and retain artery-tuned mechanics and surface heparin at two weeks. While further testing is warranted, these results indicate that H-ENGs satisfy the three prerequisites for vascular graft clinical success. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=68 SRC="FIGDIR/small/701857v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1e09f2aorg.highwire.dtl.DTLVardef@1f1b5baorg.highwire.dtl.DTLVardef@1d1fba6org.highwire.dtl.DTLVardef@e066ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

EXPERIMENTAL CHARACTERIZATION OF BALLOON ANGIOPLASTY IN HUMAN FEMOROPOPLITEAL ARTERIES WITH DIFFERENT CALCIUM BURDENS

IntroductionBalloon angioplasty is one of the most common treatments for Peripheral Artery Disease (PAD), but its clinical outcomes continue to disappoint, particularly when managing calcified lesions. We characterized luminal gains and damage after balloon angioplasty using high-resolution imaging, histology, and mechanical testing. MethodsFresh diseased human femoropopliteal arteries (FPA) from n=15 subjects (average age 69 {+/-} 9, range 53-90 years) with different calcium burdens were imaged before, during, and after angioplasty using micro-computed tomography, and luminal gains, calcium fractures, and resulting dissections were quantified. Histology was used to assess structural damage, and biaxial mechanical testing determined damage initiation stretches and stresses. ResultsIn severely calcified FPAs, calcification often manifested as rings or large plate-like deposits. When calcium spanned the entire circumference, angioplasty produced longitudinal cracks but [~]8% luminal area gain. In less calcified arteries, damage manifested primarily as tears along the internal elastic lamina and within the tunica media. Dissections were present in 53% of all FPAs after angioplasty, with a higher prevalence in more calcified vessels and vessels with stenosis (75% each). Damage initiated at lower biaxial stretches (1.11 {+/-} 0.02 vs 1.14-1.15) and lower longitudinal stresses (44 {+/-} 22 kPa vs 57 {+/-} 31 kPa) in severely calcified specimens compared with lightly calcified arteries, but larger calcium burdens generally required more circumferential stress to initiate damage (66 {+/-} 27 kPa). Diabetes mellitus was associated with a higher calcium burden. ConclusionsSevere calcification limits luminal gains after angioplasty. Less calcified arteries accumulate damage to the healthier wall while calcium remains mostly intact. These results may inform clinical strategies and the development of better devices to treat PAD.

bioengineering↗

bioRxiv2025

NITINOL MATERIAL PROPERTIES OF 11 COMMERCIAL PERIPHERAL STENTS DETERMINED USING INVERSE COMPUTATIONAL ANALYSIS

Stent-artery interactions are influenced by the mechanical properties of self-expanding Nitinol stents, but data on these characteristics remain limited. Eleven stents (Absolute Pro, S.M.A.R.T. Control, Misago, Zilver, Complete SE, EverFlex, Innova, Pulsar-18, LifeStent, S.M.A.R.T. Flex, and Supera) used to treat peripheral arterial disease (PAD) were subjected to axial tension, compression, three-point bending, and torsion tests, and the data on reaction forces and moments were compared with finite element simulations of the same experiments. Inverse computational analysis was used to determine austenite and martensite elasticity, transformation stretch, stresses at the start and end of transformation loading, and the start of transformation stress in compression. Uniaxial tensile tests were done on isolated struts from Absolute Pro and Zilver stents to verify the results of the inverse analysis. Our study demonstrate that Nitinol material properties are significantly different across devices. Austenite elasticity ranged 7.5-85 GPa, martensite elasticity 10-47.8 GPa, transformation stretch 1.03-1.08, the start of transformation loading stress 386-465 MPa, the end of transformation loading stress 411-535 MPa, and the start of transformation stress in compression 150-900 MPa. Nitinol of S.M.A.R.T. Control and S.M.A.R.T. Flex devices had the softest response, while Pulsar-18 had the hardest. The presented Nitinol mechanical properties of commonly used PAD stents can improve the fidelity of computational models investigating stent-artery interactions and may help improve clinical outcomes of endovascular PAD repairs through better device design.

bioengineering↗