In situ and non-cytotoxic cross-linking strategy for 3D printable biomaterials.

3D bioprinting allows the production of patient-specific tissue constructs with desired structural characteristics such as high resolution, controlled swelling degree, and controlled degradation behavior by mostly using hydrogels. Crosslinking of hydrogels is an essential parameter in bioprinting applications, which is beneficial for tuning structural specifications. In this study, gelatin-alginate-whey protein isolate based hydrogels have been used for 3D printing structures in a layer-by-layer fashion. These structures were cross-linked by the Amino Acid (monomer) Decorated and Light Underpinning Conjugation Approach (ANADOLUCA) method, which is a unique, non-invasive photosensitive cross-linking technique for protein-based mixtures. In that aim, hydrogel properties (e.g., printability, biocompatibility, rheologic and mechanical behavior) and cross-linking properties (e.g., swelling and degradation behavior) were studied. Results were compared with UV and ionic cross-linking techniques, which are the abundantly used techniques in such studies. The results showed that the ANADOLUCA method can be used for in situ cross-linking under mild conditions for the printing of bio-inks, and the proposed method can be used as an alternative for UV-based and chemical cross-linking techniques.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors.

Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology.