Molecularly imprinted cryogel membranes for mitomycin C delivery

Experimental and Modelling Study of Controlled Release from Dextran-Based Cryogels

In this work, five different dextran-based cryogels for controlled drug release are investigated. Vitamin B12 was used as a model drug for in vitro release tests. Two different drug-loading procedures were adopted, leading to very different drug release curves. Indeed, a fast Fickian release was observed when freeze-dried samples of DEX40PEG360MA and DEX40PEG500MA were infused with the drug after cryogel formation. On the contrary, a slowed highly non-Fickian behavior arises when the drug is loaded before the low-temperature crosslinking step, leading to the cryogel formation. The non-Fickian drug release, observed for all the five different dextran-based cryogels investigated, is actually due to the cryoconcentration phenomenon, modeled with a two-step release process. The proposed transport model accurately predicts experimental release curves characterized by a long lag time, confirming that dextran-based cryogels are suitable for controlled release.

Molecular imprinted based microcryogels for thrombin purification

In addition to understanding and explaining the functions of proteins, the need for low-cost, easy and efficient purification methods has been increasing in the field of protein purification, which is also important for enzyme production. In this context, an alternative approach has been developed for the purification of thrombin, which has a crucial role in the hemostatic process, via thrombin imprinted microcryogels that allow reuse and have high selectivity. The characterization studies of the microcryogels were accomplished with micro-computed tomography (µCT), scanning electron microscopy (SEM), optical microscope, surface area measurements (BET analyses) and swelling test measurements. By scanning various parameters affecting thrombin adsorption, the maximum thrombin adsorption capacity (Qmax) was found to be 55.86 mg/g. Also, the selectivity of microcryogels was investigated with the competitive agents and reusability studies were performed. The purity of thrombin was evaluated by Fast Performance Liquid Chromatography (FPLC) method. Experimental results indicated that adsorption of thrombin by the developed microcryogels fit the Langmuir isotherm model (Qmax: 55.86 mg/g, R2: 0.9505) and pseudo-second order for three different thrombin concentrations (R2: 0.9978, R2: 0.9998, R2: 0.9999).

Cryogels: Advancing Biomaterials for Transformative Biomedical Applications

Cryogels, composed of synthetic and natural materials, have emerged as versatile biomaterials with applications in tissue engineering, controlled drug delivery, regenerative medicine, and therapeutics. However, optimizing cryogel properties, such as mechanical strength and release profiles, remains challenging. To advance the field, researchers are exploring advanced manufacturing techniques, biomimetic design, and addressing long-term stability. Combination therapies and drug delivery systems using cryogels show promise. In vivo evaluation and clinical trials are crucial for safety and efficacy. Overcoming practical challenges, including scalability, structural integrity, mass transfer constraints, biocompatibility, seamless integration, and cost-effectiveness, is essential. By addressing these challenges, cryogels can transform biomedical applications with innovative biomaterials.

Preparation of lysozyme loaded gelatin microcryogels and investigation of their antibacterial properties

Antibacterial micron-sized cryogels, so-called microcryogels, were prepared by cryogelation of gelatin and integration of lysozyme. Gelation yield, specific surface area, macro-porosity and swelling degree of the microcryogels were examined in order to characterize their physical properties. MTT method was utilized to measure cell viability of the gelatin microcryogels with a period of 24, 48, and 72 h and no significant decrease was observed at 72 h. Apoptotic staining assay also showed high viability at 24, 48, 72 h in parallel with the control group. The antibacterial performances of the gelatin microcryogels against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli were examined. The results showed that the incorporation of lysozyme into gelatin microcryogels exhibited the antibacterial activity against S. aureus, B. subtilis, and E. coli, that may provide great potential for various applications in the biomedical industry.

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

In spite of technological progress, most of the current techniques for 2,4,6-trinitrotoluene (TNT) detection are time consuming due to laborious sensor preparation. Thereby, the aim of this work was to enlarge the knowledge for preparing sensitive elements for TNT with the aid of molecular imprinting; a known technique used to deliver biomimetic materials. The study first depicts the auto-assembly mechanism of (TNT) with functional diamino-silanes (i.e., N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane), via “double” Meisenheimer complexes. This mechanism is being described herein for the first time and applied further to obtain molecularly imprinted polymer (MIP) films for TNT recognition. For testing the potential application of films as chemical sensor elements, typical rebinding assays of TNT in a liquid state and the rebinding of TNT in a vapor state, using multilayered sensor chips composed of quartz-chromium (Cr)-gold (Au)-titanium oxide (TiO2), were employed. Batch rebinding experiments have shown that thinner films were more efficient on retaining TNT molecules in the first five min, with a specificity of about 1.90. The quartz-Cr-Au-TiO2-MIP capacitive sensors, tested in vapor state, registered short response times (less than 25 s), low sensitivity to humidity and high specificity for TNT.

Cholesterol removal from human plasma with biologically modified cryogels

In this study, low molecular weight heparin immobilized P(HEMA) cryogels were fabricated for the removal of LDL-C in hypercholesterolemic human plasma. After characterization studies for P(HEMA) cryogels, effects of the parameters including medium pH, CNBr concentration, heparin concentration and contact time on heparin immobilization were investigated. Blood compatibility and cell adhesion tests were also performed, and platelet and leucocyte loss for P(HEMA)-Hp cryogels were found to be 2.95% and 4.91%, respectively. Maximum adsorption capacity for LDL-C from hypercholesterolemic human plasma was found to be 26.7 mg/g for P(HEMA)-Hp cryogel while it was only 1.67 mg/g for bare P(HEMA) cryogel. The P(HEMA)-Hp cryogels exhibit high desorption ratios up to 96% after 10 adsorption-desorption cycles with no significant decrease in the adsorption capacity. The findings indicated that these reusable P(HEMA)-based cryogels proposed good alternative adsorbents for removal of LDL-C.

Supermacroporous Composite Cryogels in Biomedical Applications

Supermacroporous gels, called cryogels, are unique scaffolds that can be prepared by polymerization of monomer solution under sub-zero temperatures. They are widely used in many applications and have significant potential biomaterials, especially for biomedical applications due to their inherent interconnected supermacroporous structures and easy formation of composite polymers in comparison to other porous polymer synthesis techniques. This review highlights the fundamentals of supermacroporous cryogels and composite cryogels, and then comprehensively summarizes recent studies in preparation, functionalization, and utilization with mechanical, biological and physicochemical features, according to the biomedical applications. Furthermore, conclusions and outlooks are discussed for the use of these promising and durable supermacroporous composite cryogels.

Biomedical Applications of Polymeric Cryogels

The application of interconnected supermacroporous cryogels as support matrices for the purification, separation and immobilization of whole cells and different biological macromolecules has been well reported in literature. Cryogels have advantages over traditional gel carriers in the field of biochromatography and related biomedical applications. These matrices nearly mimic the three-dimensional structure of native tissue extracellular matrix. In addition, mechanical, osmotic and chemical stability of cryogels make them attractive polymeric materials for the construction of scaffolds in tissue engineering applications and in vitro cell culture, separation materials for many different processes such as immobilization of biomolecules, capturing of target molecules, and controlled drug delivery. The low mass transfer resistance of cryogel matrices makes them useful in chromatographic applications with the immobilization of different affinity ligands to these materials. Cryogels have been introduced as gel matrices prepared using partially frozen monomer or polymer solutions at temperature below zero. These materials can be produced with different shapes and are of interest in the therapeutic area. This review highlights the recent advances in cryogelation technologies by emphasizing their biomedical applications to supply an overview of their rising stars day to day.

Controlled release of mitomycin C from PHEMAH-Cu(II) cryogel membranes

Molecular imprinting technique was used for the preparation of antibiotic and anti-neoplastic chemotherapy drug (mitomycin C) imprinted cryogel membranes (MMC-ICM). The membranes were synthezied by using metal ion coordination interactions with N-methacryloyl-(l)-histidine methyl ester (MAH) functional monomer and template molecules (i.e. MMC). The 2-hydroxyethyl methacrylate (HEMA) monomer and methylene bisacrylamide (MBAAm) crosslinker were used for the preparation of mitomycin C imprinted cryogel membranes by radical suspension polymerization technique. The imprinted cryogel membranes were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and swelling degree measurements. Cytotoxicity of MMC-ICMs was investigated using mouse fibroblast cell line L929. Time-dependent release of MMC was demonstrated within 150 h from cryogel membranes. Cryogels demonstrated very high MMC loading efficiency (70-80%) and sustained MMC release over hours.