4D-printed microneedles from dual-sensitive chitosan for non-transdermal drug delivery.

Microneedles are a promising micro-scale drug delivery platform that has been under development for over two decades. While 3D printing technology has been applied to fabricate these systems, the challenge of achieving needle sharpness remains. In this study, we present an innovative approach for microneedle fabrication using digital light processing (DLP) 3D printing and smart chitosan biomaterial. For the first time, we used hydroxybutyl methacrylated chitosan (HBCMA), which possesses dual temperature- and photo-sensitive properties, to create microneedles. The DLP approach enabled a quick generation of HBCMA-based microneedles with a high resolution. The microneedles exhibited 4D properties with a change in needle dimensions upon exposure to temperature, which enhances resolution, sharpens needles, and improves mechanical strength. We demonstrated the ability of these microneedles to load, deliver, sustained release small molecular drugs and penetrate soft tissue. Overall, the HBCMA-based microneedles show promising potential in non-dermal drug delivery applications.

Elaboration of dimensional quality in 3D-printed food: Key factors in process steps.

Three-dimensional (3D) printing has been applied to produce food products with intricate and fancy shapes. Dimensional quality, such as dimensional stability, surface smoothness, shape fidelity, and resolution, are essential for the attractive appearance of 3D-printed food. Various methods have been extensively studied and proposed to control the dimensional quality of printed foods, but few papers focused on comprehensively and deeply summarizing the key factors of the dimensional quality of printed products at each stage-before, during, and after printing-of the 3D printing process. Therefore, the effects of pretreatment, printing parameters and rheological properties, and cooking and storage on the dimensional quality of the printed foods are summarized, and solutions are also provided for improving the dimensional quality of the printed products at each step. Before printing, incorporating additives or applying physical, chemical, or biological pretreatments can improve the dimensional quality of carbohydrate-based, protein-based, or lipid-based printed food. During printing, controlling the printing parameters and modifying the rheological properties of inks can affect the shape of printed products. Furthermore, post-processing is essential for some printed foods. After printing, changing formulations, incorporating additives, and selecting post-processing methods and conditions may help achieve the desired shape of 3D-printed or 4D-printed products during cooking. Additives help in the storage stability of printed food. Finally, various opportunities have been proposed to regulate the dimensional properties of 3D-printed structures. This review provides detailed guidelines for researchers and users of 3D printers to produce various printed foods with the desired shapes and appearances.

Baseline micronucleus frequencies and 60Co cytokinesis-block micronucleus assay dose-response curve for biodosimetry in Vietnam.

This study aims to establish baseline micronucleus (MN) frequencies from various populations of residents in Vietnam and develop a 60Co dose-response curve for the cytokinesis-block micronucleus (CBMN) assay. Blood samples were exposed in vitro to a 60Co source at a dose rate of 275 mGy per min in a range of 0.1 to 4.0 Gy. MN background frequencies were 4.5 ± 3.2, 7.3 ± 4.6, 7.0 ± 3.8 and 13.1 ± 6.7 in 1000 binucleated (BN) cells for 96 healthy donors, 22 male radiation workers and 12 breast cancer patients, respectively. Blood samples from three healthy donors were used to generate the MN dose-response curve: y = C + (0.0496 ± 0.0069)D + (0.0143 ± 0.0026)D2. This curve was verified through an inter-laboratory comparison (RENEB ILC 2021). Our findings highlight the significance of the CBMN assay as an additional essential tool for biodosimetry in Vietnam.

Triple-conjugated photo-/temperature-/pH-sensitive chitosan with an intelligent response for bioengineering applications.

Hybrid-crosslinked systems, which can be formed using heat and visible light, are significant for improving the stability of hydrogels under physiological conditions. However, several challenges for their practical application remain, such as shrinking under culture medium conditions or the neutral pH in the small intestine. Therefore, a multi-sensitive hydrogel with response to external conditions has been designed and prepared, which could be employed as a biopolymer ink formulation for three-dimensional printing in bioengineering applications. When exposed to body temperature and visible light, the N-succinyl hydroxybutyl methacrylated chitosan (NS-HBC-MA) undergoes a sol-gel phase transition. The NS-HBC-MA hydrogel exhibits pH-responsive swelling, effectively preventing shrinkage at a neutral pH. Furthermore, NS-HBC-MA hydrogel demonstrates excellent biocompatibility and biodegradability. This study demonstrates that the NS-HBC-MA hydrogel has significant potential for various applications, including wound healing, delivery systems, and tissue engineering.

Potato starch altered the rheological, printing, and melting properties of 3D-printable fat analogs based on inulin emulsion-filled gels.

Plant-based oil inks that imitate the texture and melting behavior of traditional animal fats using 3D printing have been developed. The influence of the incorporation of potato starch and the type of oil on rheology and meltability was investigated. The results showed that the dynamic modulus and hardness of fat analogs increased, whereas fat analog meltability decreased with an increase in potato starch content. Coconut oil and soybean oil-containing fat analogs incorporated with proper potato starch levels exhibited good printability and similar meltability to commercial beef and pork fats. The addition of potato starch suppressed fat analog meltability as it disrupted the inulin matrix. Fat analogs containing coconut oil could be texturized at temperatures lower than those required for their soybean oil counterparts. The fat analogs were solid at room temperature, demonstrated good printability, and imitated the melting behavior of fat contained in real meat throughout the cooking process.

Determination of spontaneous dicentric frequencies and establishment of dose-response curves after expose of human peripheral blood lymphocytes to low- and high-dose rate 60Co gamma rays - the basis for cytogenetic biodosimetry in Vietnam.

PURPOSE: The purposes of this study are to investigate spontaneous dicentric frequencies and dose-response curves of dicentrics induced by gamma 60Co for replenishing the data sets used for biodosimetry in Vietnam. MATERIALS AND METHODS: One hundred and four healthy donor blood samples were collected for chromosome aberrations background study, 03 healthy donor blood samples were used for generating the dose-response curves at 1.96 mGy/min and 275 mGy/min. Blood collection, in vitro irradiation, cell culture and harvest, slide preparation and metaphase scoring were performed according to IAEA standard protocol (2011). Blind exposed samples were scored for verifying each curve. RESULTS: The dicentric, fragment and chromatid break frequencies in 106,310 metaphases of 104 donors were 0.023% ± 0.005%, 0.045% ± 0.007% and 0.101% ± 0.011%, respectively. The dose-response curve for low-dose rate was y = C + (0.0137 ± 0.0055)D + (0.0912 ± 0.0142)D2 and for high-dose rate was y = C + (0.0337 ± 0.0046)D + (0.0539 ± 0.0031)D2, where both of them were verified. CONCLUSION: The data of this study were established for biological dose assessment in cases with low LET of accidental or occupational radiation exposures in the dose range of 0.1-5.0 Gy.