arXiv subjects

Jerker Widengren

Publications and source records attributed to Jerker Widengren.

4 recordsLinked to original sources

arXiv2026

Optical-Memory Transport Imaging: Extension to Stochastic Diffusion

Finite-memory optical tracers can encode transport properties through their previously experienced excitation. Using such memory features, harboured in the population of excitable long-lived electronic states within the emitters, instantaneous localization assessments are not needed to determine their transport properties. Here we formulate this principle for monitoring of stochastic transport extracted from transport-history integral over conditional transport histories. Under structured illumination, this history yields a measurable transfer-function response from which scalar and tensor diffusion are reconstructed without time-resolved acquisition. Fisher-information analysis identifies the optimal operating regime and yields first-principles, parameter-free predictions of scalar and tensor reconstruction precision, in quantitative agreement with independent Monte Carlo simulations. These results establish finite optical memory as a general principle for stochastic transport imaging.

physics.optics↗

arXiv2026

Optical-Memory Transport Imaging: A Transport-History Framework for Finite-Memory Tracers

Finite-memory optical tracers encode upstream transport histories rather than instantaneous local flow velocities. We introduce optical-memory transport (OMT) imaging, a framework in which finite memory couples internal-state relaxation to transport through memory kernels. Under structured illumination, these histories are converted into measurable complex spatial-frequency response, whose local transfer-function limit yields constant-velocity inversion. Fisher-information analysis establishes kernel-dependent information limits and design principles for finite-memory transport imaging.

physics.optics↗

arXiv2025

Lanthanide upconversion nonlinearity: a key probe feature for background-free deep-tissue imaging

Lanthanide-based upconversion nanoparticles (UCNPs) have attracted considerable attention in biomedical applications, largely due to their anti-Stokes shifted emission enabling autofluorescence-free signal detection. However, residual excitation light can still interfere with their relatively low brightness. While commonly used lock-in detection can distinguish weak signals from substantial random background, concurrently modulated residual excitation light is not eliminated. This remains a challenge, particularly under demanding experimental conditions. Here, we explore the inherent nonlinear response of UCNPs and discover that UCNPs can act as frequency mixers in response to intensity-modulated excitation. Particularly, modulated excitation with more than one base modulation frequency can generate additional low-frequency beating-signals. We show how these signals are resolvable by low-speed detectors such as cameras, are devoid of ambient and residual excitation light, and how they can be enhanced through nanoparticle engineering. Detection of beating-signals thus provides a strategy to significantly enhance signal-to-background conditions in UCNP-based bioimaging and biosensing.

physics.optics↗

arXiv2023

Antibody-loading of biological nanocarrier vesicles derived from red-blood-cell membranes

Antibodies, disruptive potent therapeutic agents against pharmacological targets, face a barrier crossing immune-system and cellular-membranes. To overcome these, various strategies have been explored including shuttling via liposomes or bio-camouflaged nanoparticles. Here, we demonstrate the feasibility to load antibodies into exosome-mimetic nanovesicles derived from human red-blood-cell-membranes. The goat-anti-chicken antibodies are loaded into erythrocyte-membrane derived nanovesicles and their loading yields are characterized and compared with smaller dUTP-cargo. Applying dual-color coincident fluorescence burst methodology, the loading yield of nanocarriers is profiled at single-vesicle level overcoming their size-heterogeneity and achieving a maximum of 38-41% antibody-loading yield at peak radius of 52 nm. The average of 14 % yield and more than two antibodies per vesicle is estimated, comparable to those of dUTP-loaded nanovesicles after additional purification through exosome-spin-column. These results suggest a promising route for enhancing biodistribution and intracellular accessibility for therapeutic antibodies using novel, biocompatible, and low-immunogenicity nanocarriers, suitable for large-scale pharmacological applications.

physics.bio-ph↗