RESUMO
Hyperpigmentation is one of the most common skin disorder that affects both men and women of all ethnic groups, caused by several factors, such as UV exposure and skin inflammation. Topical whitening agents were found to be the best and the least aggressive therapy for treating hyperpigmentation compared to instrumental approaches. However, topical treatment faces several obstacles due to the low stability of the whitening agents. Therefore, the encapsulation of these agents was found to be crucial as it enhances their physicochemical stability and increases their concentration at the targeted site via an improved skin permeation, penetration or distribution. In this article, we review the literature aimed to enhance the stability and the targeting of skin whitening agents through their encapsulation in various nano and micro-particulate systems.
Assuntos
Composição de Medicamentos , Preparações Clareadoras de Pele/farmacologia , Administração Tópica , Humanos , Hiperpigmentação/tratamento farmacológico , Pele , Absorção CutâneaRESUMO
Proteinases are involved in a multitude of important physiological processes, such as protein metabolism. For this reason, a conductometric enzyme biosensor based on proteinase K was developed using two types of nanoparticles (gold and magnetic). The enzyme was directly adsorbed on negatively charged nanoparticles and then deposited and cross-linked on a planar interdigitated electrode (IDE). The biosensor was characterized with bovine serum albumin (BSA) as a standard protein. Higher sensitivity was obtained using gold nanoparticles. The linear range for BSA determination was then from 0.5 to 10 mg/L with a maximum response of 154 µs. These results are greater than that found without any nanoparticles (maximum response of 10 µs). The limit of detection (LOD) was 0.3 mg/L. An inter-sensor reproducibility of 3.5% was obtained.
Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Condutometria/instrumentação , Condutometria/métodos , Endopeptidase K/química , Nanopartículas Metálicas/química , Ouro/química , Limite de Detecção , Magnetismo/instrumentação , Magnetismo/métodos , Sensibilidade e Especificidade , Soroalbumina Bovina/químicaRESUMO
The aim of this study was to show the feasibility and the performances of nanoparticle biosensing. A glucose conductometric biosensor was developed using two types of nanoparticles (gold and magnetic), glucose oxidase (GOD) being adsorbed on PAH (poly(allylamine hydrochloride)) modified nanoparticles, deposited on a planar interdigitated electrode (IDEs). The best sensitivities for glucose detection were obtained with magnetic nanoparticles (70 µM/mM and 3 µM of detection limit) compared to 45 µM/mM and 9 µM with gold nanoparticles and 30 µM/mM and 50 µM with GOD directly cross-linked on IDEs. When stored in phosphate buffer (20 mM, pH 7.3) at 4 °C, the biosensor showed good stability for more than 12 days.
