Forces are central to countless cellular processes, yet in vivo force measurement at the molecular scale remains difficult if not impossible. During clathrin-mediated endocytosis, forces produced by the actin cytoskeleton are transmitted to the plasma membrane by a multiprotein coat for membrane deformation. However, the magnitudes of these forces remain unknown. Here, we present new in vivo force sensors that induce protein condensation under force. We measured the forces on the fission yeast Huntingtin-Interacting Protein 1 Related (HIP1R) homolog End4p, a protein that links the membrane to the actin cytoskeleton. End4p is under ~19-piconewton force near the actin cytoskeleton, ~11 piconewtons near the clathrin lattice, and ~9 piconewtons near the plasma membrane. Our results demonstrate that forces are collected and redistributed across the endocytic machinery.

The Raman spectra of human blood serum can be used to identify cancer or other diseases; however, obtaining a reliable surface enhanced Raman scattering (SERS) signal of human blood serum is difficult. Two primary factors that affect SERS measurement of serum are photodegradation and sample composition, which are investigated in this research. In the end, this research proposes a promising set of measurement conditions that can both acquire reliable serum Raman signals and avoid photodegradation.

The long-term stability of Pickering emulsions is crucial for their application in food systems. This study aimed to evaluate the stability degradation of oil-in-water (O/W) Pickering emulsions stabilized by whey protein isolate (WPI) and chitosan (CS), and to assess their applicability in reduced-fat mayonnaise formulations. Optical tweezers were employed to quantify the interaction forces between emulsion droplets during storage, in combination with microstructural observation and ζ-potential analysis. It was found that the O/W emulsion prepared with a 50% aqueous phase volume fraction maintained a stable droplet size over the storage period without significant changes. The ζ-potential decreased from 79.16 mV to 53.62 mV, while the maximum droplet contact force gradually decreased from 69 pN to 37 pN by day 45. By day 60, droplet coalescence was observed. Compared with traditional rice bran oil mayonnaise, the mayonnaise formulated using this Pickering emulsion exhibited superior mechanical stability and resistance to destabilization. In particular, the formulation with a Pickering emulsion-to-egg yolk volume ratio of 4:1 showed the best mechanical performance, with the droplet contact force gradually decreasing from 68 pN on day 0 to 62 pN on day 20. This study provides a rapid method for evaluating the stability of food systems, offering potential applications in the food industry.