Characterization of polystyrene microplastic

• Grant number: 25/05508-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Rodrigo Bueno de Oliveira
• Grantee: Julya Sampaio de Medeiros
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 24/09308-2 - INFLUENCE OF POLYSTYRENE MICROPLASTIC ON THE DEVELOPMENT OF OSTEOPOROSIS - ANALYSIS IN WISTAR RATS, AP.R

Abstract

Introduction: Experimental data show that polystyrene, a type of microplastic (MP), is implicated in the reduction of bone mass, number of trabeculae and its increased spacing, in addition to the reduction of the size of long bones in pubertal mice, through the acceleration of osteoblast senescence, by the reduction of the expression of the Runx2 gene, among other factors. Recently, it was described that male mice exposed to MP present an imbalance in the bone remodelling process, due to the impairment in the differentiation of osteoclasts and osteoblasts, resulting in the decrease of bone mass, decreased bone formation and activation of osteoclasts. The working hypothesis is that the cumulative exposure to polystyrene causes worsening of the progression of osteoporosis in ovariectomized rats, for this reason, the characterisation prior to the administration of MPs to the animal model is crucial. Aim: to characterise polystyrene MPs prior to the analysis of osteoporosis development. Materials and methods: Fluoresbrite® polystyrene MPs of 0.5 µm (#18339-10) will be obtained and characterised prior to administration to the animal model by different analytical techniques (SEM, FTIR, fluorescence and Raman). For SEM, three aliquots of 20 µL will be obtained and applied by light smearing in a single direction onto adhesive carbon tape and dried at room temperature protected from light. Representative microphotographs obtained will be exported in .tiff format for this qualitative analysis. For FTIR, FTIR spectra of three samples will be acquired using a Nicolet Summit FTIR equipped with an Everest ATR with a diamond crystal plate and a DTGS KBr detector. The background will be measured with the same settings in correspondence to the air. For characterisation using fluorescence microscopy, the excitation parameters of 360 nm and emission of 407 nm will be adopted for the visualization of the MPs samples under fluorescence (according to the manufacturer). Different magnifications and particle clustering patterns of MPs will be recorded in order to obtain baseline data for the following analyses. For the Raman analysis, polystyrene microspheres will be prepared and examined using a microscope and the obtained peaks will be compared and identified with data from Raman databases https://rruff.info/ and/or https://ramanlife.com/library/polystyrene-raman/. In this sense, the characterisation will provide crucial knowledge of the MPs for the subsequent investigations. Dissemination: publication of a scientific article and dissemination of the results at national and international events.