Synthesis and Functionalization of Biodegradable Second Harmonic Generation Nanoprobes for Cell Targeting.

Optical imaging technologies and cell targeting have played a major role in detecting and treating diseases such as cancer. Bioharmonophores are optical imaging nanoprobes composed of biodegradable polymer-encapsulated, self-assembling triphenylalanine peptides. They produce a strong second harmonic generation (SHG) signal, a non-linear optical process in which two photons directed at a non-centrosymmetric medium combine to form a new photon with twice the energy. Bioharmonophores demonstrate superior optical properties compared to fluorescent probes and, unlike previously developed inorganic SHG nanoprobes, are both biocompatible and biodegradable. Here, we present a protocol providing five detailed procedures that describe (1) synthesis of bioharmonophores; (2) embedding and imaging of the synthesized SHG nanoprobes in polyacrylamide gel; (3) functionalization of bioharmonophores with thiol-containing polyethyleneglycol; (4) subsequent click chemistry to target cancer cells; and (5) imaging of functionalized bioharmonophores endocytosed by cancer cells using two-photon microscopy. Bioharmonophores hold great potential as clinical contrast agents due to their optical features and could be used in the future as an innovative approach to cancer treatment using targeted high-resolution optical imaging. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Synthesis of bioharmonophores Basic Protocol 2: Imaging of bioharmonophores in polyacrylamide gel Basic Protocol 3: Functionalization of bioharmonophores with thiol-PEG Basic Protocol 4: Functionalization of thiol-PEGylated bioharmonophores with peptides Basic Protocol 5: Targeting of cancer cells with functionalized bioharmonophores.

Synthesis of grafted bromoisobutyryl esterified starch using electron transfer atom transfer radical polymerization method with high-performance adhesion and film properties.

Nowadays, few investigations on the process parameters of grafted starch synthesized using electron transfer atom transfer radical polymerization (ARGET ATRP) and its applications in warp sizing and paper-making are presented. Therefore, this study aimed to survey the appropriate process parameters of bromoisobutyryl esterified starch-g-poly(acrylic acid) (BBES-g-PAA) synthesized by the ARGET ATRP, and also aimed to provide a new biobased BBES-g-PAA adhesive. The appropriate synthesis process parameters were 1.2, 0.32, and 0.6 in the molar ratios of vitamin C, CuBr2, and pentamethyldivinyltriamine to BBES, respectively, at 40 °C for 5 h. The BBES-g-PAA samples with a grafting ratio range of 4.63-14.14 % exhibited bonding forces of 57.8-64.6 N to wool fibers [55.5 N (BBES) and 53.8 N (ATS)], and their films showed breaking elongations of 3.29-3.80 % [2.74 % (BBES) and 2.49 % (ATS)] and tensile strengths of 29.1-25.4 MPa [30.4 MPa (BBES) and 34.7 MPa (ATS)]. Compared with BBES, significantly increased bonding forces and film elongations, and decreased film strengths for the BBES-g-PAA samples with grafting ratios ≥10.54 % were displayed (p < 0.05). The time (100-42 s) taken for the BBES-g-PAA films was significantly shorter than that of ATS (246 s) and BBES (196 s) films (p < 0.05), corresponding to better desizability.

Chitosan-PNIPAM Thermogel Associated with Hydrogel Microspheres as a Smart Formulation for MSC Injection.

Regenerative medicine based on cell therapy has emerged as a promising approach for the treatment of various medical conditions. However, the success of cell therapy heavily relies on the development of suitable injectable hydrogels that can encapsulate cells and provide a conducive environment for their survival, proliferation, and tissue regeneration. Herein, we address the medical need for cyto- and biocompatible injectable hydrogels by reporting on the synthesis of a hydrogel-forming thermosensitive copolymer. The copolymer was synthesized by grafting poly(N-isopropylacrylamide-co-carboxymethyl acrylate) (PNIPAM-COOH) onto chitosan through amide coupling. This chemical modification resulted in the formation of hydrogels that exhibit a sol-gel transition with an onset at approximately 27 °C, making them ideal for use in injectable applications. The hydrogels supported the survival and proliferation of cells for several days, which is critical for cell encapsulation. Furthermore, the study evaluates the addition of collagen/chitosan hybrid microspheres to support the adhesion of mesenchymal stem cells within the hydrogels. Altogether, these results demonstrate the potential of the PNIPAM-chitosan thermogel for cell encapsulation and its possible applications in regenerative medicine.

Block Copolymers of Polyolefins with Polyacrylates: Analyzing and Improving the Blocking Efficiencies Using MILRad/ATRP Approach.

Despite their industrial ubiquity, polyolefin-polyacrylate block copolymers are challenging to synthesize due to the distinct polymerization pathways necessary for respective blocks. This study utilizes MILRad, metal-organic insertion light-initiated radical polymerization, to synthesize polyolefin-b-poly(methyl acrylate) copolymer by combining palladium-catalyzed insertion-coordination polymerization and atom transfer radical polymerization (ATRP). Brookhart-type Pd complexes used for the living polymerization of olefins are homolytically cleaved by blue-light irradiation, generating polyolefin-based macroradicals, which are trapped with functional nitroxide derivatives forming ATRP macroinitiators. ATRP in the presence of Cu(0), that is, supplemental activators and reducing agents , is used to polymerize methyl acrylate. An increase in the functionalization efficiency of up to 71% is demonstrated in this study by modifying the light source and optimizing the radical trapping condition. Regardless of the radical trapping efficiency, essentially quantitative chain extension of polyolefin-Br macroinitiator with acrylates is consistently demonstrated, indicating successful second block formation.

Synthesis, Characterization, and Investigation of Doxorubicin Drug Release Properties of Poly(acrylamide-co-acrylic Acid/Maleic Acid)-Hydroxyapatite Composite Hydrogel.

BACKGROUND: Hydroxyapatite and its derivatives have been used for a lot of applications. One of them is drug release studies. Due to its low adhesion strength and lack of the strength and durability required for load-carrying applications, there is a need to improve the properties of hydroxyapatite. For this aim, the most important factors are increasing pH sensitivity and preventing coagulation. Mixing it with multifunctional polymers is the best solution. OBJECTIVES: The main objectives are: 1- preparing poly(acrylamide-co-acrylic acid/maleic acid)- hydroxyapatite (PAm-co-PAA/PMA-HApt), 2- assessment of (PAm-co-PAA/PMA-HApt) and dox-loaded poly(acrylamide-co-acrylic acid/maleic acid) (Dox-(PAm-co-PAA/PMA-HApt)) composite hydrogels, and 3- elucidating the difference in behavior of drug release studies between hydroxyapatite (HApt) and poly(acrylamide-co-acrylic acid/maleic acid) composite hydrogels. METHODS: A composite of PAm-co-PAA/PMA-HApt was prepared by direct polymerization of acrylamide-co-acrylic acid/maleic acid in a suspension of HApt. The drug loading and release features of PAm-co-PAA/PMA-HApt and HApt were then investigated for doxorubicin (dox) release. Using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TG/DTA), this unique composite hydrogel has been physicochemically investigated. Also, a colorimetric assay was used to assess the in vitro biocompatible support and anticancer activity of HApt and the newly developed composite hydrogel XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay. RESULTS: According to the results of drug release studies of this new material, it is pH sensitive, and PAm-co-PAA/PMA-HApt demonstrated a faster release than HApt at 37°C in the acidic solution of pH 4.5 than in the neutral solution of pH 7.4. The XTT assay outcomes also demonstrated the biocompatibility of PAm-co-PAA/PMA-HApt and HApt and the cytotoxic effect of dox-loaded PAm-co-PAA/PMA-HApt. CONCLUSION: It should be inferred that the drug release profile was improved at pH 4.5 by the newly produced pH-sensitive composite hydrogel.

Fracasos en la adhesión / Adhesion failures

Los fracasos en la adhesión se van a traducir en fallos a distintos niveles de las distintas interfases. Puede haber:(1) fallos adhesivos entre esmalte y material adhesivo, dentina y material adhesivo, resina compuesta y materialadhesivo; o (2) fallos cohesivos en esmalte, dentina, resina compuesta, material adhesivo. Se examinan las distintasrazones que los provocan así como los factores que influyen en las interfases estudiadas (AU)

The failures in adhesion will turn into failures at different levels of the interface. There can be (1) adhesive failures,between the enamel and the adhesive material, dentine and the adhesive material, composite and the adhesivematerial; or (2) cohesive failures, in enamel, dentine, composite or adhesive material. The different reasons thatlead to such situation as well as the aspects that influence the studied interfaces are analysed here (AU)