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Direct measurements to determine the degree of surface coverage of nanoparticles by functional moieties are rare, with current strategies requiring a high level of expertise and expensive equipment. Here, a practical method to determine the ratio of the volume of the functionalisation layer to the particle volume based on measuring the refractive index of nanoparticles in suspension is proposed. As a proof of concept, this technique is applied to poly(methyl methacrylate) (PMMA) nanoparticles and semicrystalline carbon dots functionalised with different surface moieties, yielding refractive indices that are commensurate to those from previous literature and Mie theory. In doing so, it is demonstrated that this technique is able to optically detect differences in surface functionalisation or composition of nanometre-sized particles. This non-destructive and rapid method is well-suited for industrial particle characterisation and biological applications.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9178438 | PMC |
http://dx.doi.org/10.1039/d2nr00120a | DOI Listing |
Graefes Arch Clin Exp Ophthalmol
September 2025
Department of Physics of Condensed Matter, Optics Area. Vision Research Group (CIVIUS), University of Seville, Avenida de la Reina Mercedes s/n (41012), Seville, Spain.
Purpose: To analyze the relationship between various visual function parameters (refractive status, visual acuity and contrast sensitivity) and macular pigment optical density (MPOD) values, as well as dietary intake of lutein and zeaxanthin in a pediatric population.
Methods: Thirty-six healthy White pediatric patients participated in this cross-sectional study conducted at the Optometry Clinic (Faculty of Pharmacy, Seville, Spain). MPOD values were measured using the MPSII (Macular Pigment Screener II).
Invest Ophthalmol Vis Sci
September 2025
Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
Purpose: The purpose of this study was to investigate the focal relationship between choroidal thickness and retinal sensitivity in myopic eyes.
Methods: Participants underwent swept-source optical coherence tomography (SS-OCT) imaging and microperimetry testing. Choroidal thicknesses were obtained by segmenting the SS-OCT scans using a deep-learning approach.
J Refract Surg
September 2025
Department of Refractive Surgery, Shanghai Aier Eye Hospital, Shanghai.
Purpose: To analyze the effects of ablation interruption on ablation depths and clinical refractive outcomes to characterize the impact of ambient temperature changes and ablation interruption on ocular surface temperature (OST) during excimer laser ablation.
Methods: This prospective study was conducted on laser ablations in polymethylmethacrylate (PMMA) plates and porcine corneas to simulate laser in situ keratomileusis (LASIK) treatments using the EX500 laser (Alcon Laboratories, Inc) at ambient temperatures of 18, 20, and 22 °C. Ablation interruption was performed for 1, 2, 3, 4, and 5 seconds at the 10th second of the treatment of -9.
J Refract Surg
September 2025
Purpose: To discuss the technique and outcome of what the authors called the "flap-in-flap" technique and report its safety as a procedure for correction of post-laser in situ keratomileusis (LASIK) myopic regression.
Methods: Seven eyes of 4 patients were included in this study. All patients had previously undergone LASIK for compound myopic astigmatism using the Moria M2 micro-keratome (Moria) 8 to 12 years prior to presentation.
J Refract Surg
September 2025
Department of Refractive Surgery, Aier Eye Hospital, Jinan University, Guangzhou, Guangdong, China.
Purpose: To report the refractive outcome of femtosecond laser-assisted lenticule intrastromal keratoplasty (LIKE) in correcting moderate to high hyperopia. Intraoperative effective optical zone (EOZ), centration offset, and postoperative higher order aberrations (HOAs) were analyzed to better understand factors affecting postoperative outcomes.
Methods: This was a prospective, consecutive case series study of LIKE for correcting hyperopia in one department from 2018 to 2023.