Center of Nanoscience, Nanotechnology and Innovation-CeNano2I, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Av. Antônio Carlos, 6627 - Escola de Engenharia - Bloco 2 - sala 2233, Pampulha, Belo Horizonte/MG, 31.270-901, Brazil.
Molecules. 2013 Jun 4;18(6):6550-72. doi: 10.3390/molecules18066550.
Carbohydrates and derivatives (such as glycolipids, glycoproteins) are of critical importance for cell structure, metabolism and functions. The effects of carbohydrate and lipid metabolic imbalances most often cause health disorders and diseases. In this study, new carbohydrate-based nanobioconjugates were designed and synthesized at room temperature using a single-step aqueous route combining chitosan and acyl-modified chitosan with fluorescent inorganic nanoparticles. N-palmitoyl chitosan (C-Pal) was prepared aiming at altering the lipophilic behavior of chitosan (CHI), but also retaining its reasonable water solubility for potential biomedical applications. CHI and C-Pal were used for producing biofunctionalized CdS quantum dots (QDs) as colloidal water dispersions. Fourier transform infrared spectroscopy (FTIR), thermal analysis (TG/DSC), surface contact angle (SCA), and degree of swelling (DS) in phosphate buffer were used to characterize the carbohydrates. Additionally, UV-Visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), dynamic light scattering (DLS), scanning and transmission electron microscopy (SEM/TEM) were used to evaluate the precursors and nanobioconjugates produced. The FTIR spectra associated with the thermal analysis results have undoubtedly indicated the presence of N-palmitoyl groups "grafted" to the chitosan chain (C-Pal) which significantly altered its behavior towards water swelling and surface contact angle as compared to the unmodified chitosan. Furthermore, the results have evidenced that both CHI and C-Pal performed as capping ligands on nucleating and stabilizing colloidal CdS QDs with estimated average size below 3.5 nm and fluorescent activity in the visible range of the spectra. Therefore, an innovative "one-step" process was developed via room temperature aqueous colloidal chemistry for producing biofunctionalized quantum dots using water soluble carbohydrates tailored with amphiphilic behavior offering potential applications as fluorescent biomarkers in the investigation of glycoconjugates for the nutrition, biology, pharmaceutical, and medicine fields.
碳水化合物及其衍生物（如糖脂、糖蛋白）对细胞结构、代谢和功能至关重要。碳水化合物和脂质代谢失衡的影响通常会导致健康障碍和疾病。在这项研究中，设计并合成了新型基于碳水化合物的纳米生物缀合物，在室温下使用单步水相途径，将壳聚糖和酰基修饰的壳聚糖与荧光无机纳米粒子结合。N-棕榈酰壳聚糖（C-Pal）的制备旨在改变壳聚糖（CHI）的亲脂性行为，但同时保留其在潜在生物医学应用中的合理水溶性。CHI 和 C-Pal 用于制备生物功能化的 CdS 量子点（QD）作为胶体水分散体。傅里叶变换红外光谱（FTIR）、热分析（TG/DSC）、表面接触角（SCA）和在磷酸盐缓冲液中的溶胀度（DS）用于表征碳水化合物。此外，还使用紫外可见光谱（UV-Vis）、光致发光光谱（PL）、动态光散射（DLS）、扫描和透射电子显微镜（SEM/TEM）来评估所制备的前驱体和纳米生物缀合物。与热分析结果相关的 FTIR 光谱无疑表明存在“接枝”到壳聚糖链上的 N-棕榈酰基团（C-Pal），与未修饰的壳聚糖相比，它显著改变了其对水膨胀和表面接触角的行为。此外，结果表明，CHI 和 C-Pal 都可以作为成核和稳定胶体 CdS QD 的配体，其平均尺寸估计小于 3.5nm，在可见光谱范围内具有荧光活性。因此，通过室温下的水相胶体化学开发了一种创新的“一步法”工艺，用于使用具有两亲性的水溶性碳水化合物来制备生物功能化的量子点，该工艺具有潜在的应用前景，可作为营养、生物学、制药和医学领域中糖缀合物研究的荧光生物标志物。
