PFAS molecules binding to HSA in bloodstream

Are 'Forever Chemicals' Hitching a Ride in Your Bloodstream? What You Need to Know

Nico Varela in Health & Wellness August 2025 • 4 min read.

"New research reveals how PFAS chemicals bind to human serum albumin, potentially spreading these toxins throughout the body."

You've probably heard about "forever chemicals," or PFAS (per- and polyfluoroalkyl substances). These man-made chemicals are used in everything from non-stick cookware to firefighting foam, and they don't break down easily in the environment or our bodies. While some PFAS, like PFOS, have been phased out, similar chemicals are still in use, raising concerns about their potential health effects.

One of the biggest worries is how these chemicals travel through our bodies. Human serum albumin (HSA), the most abundant protein in blood, acts like a taxi service, carrying various molecules. Scientists are particularly interested in whether PFAS can bind to HSA and, if so, how this interaction might affect where these chemicals end up in the body.

New research has uncovered that specific PFAS compounds—perfluoroalkane sulfonyl fluorides (PFASFs)—can indeed bind to HSA. The study pinpoints the binding sites on HSA and explores the strength of these interactions, offering valuable insights into how these "forever chemicals" might be distributed and potentially impact our health.

PFAS and HSA: A Close Encounter

PFAS molecules binding to HSA in bloodstream

The study focused on three PFASFs: PFOSF (perfluorooctane sulfonyl fluoride), PFHSF (perfluorohexane sulfonyl fluoride), and PFBSF (perfluorobutane sulfonyl fluoride). Researchers used a technique called fluorescence spectroscopy to observe how these chemicals interact with HSA. This method allowed them to identify where the PFASFs bind on the HSA molecule.

The researchers discovered that PFASFs primarily bind to two well-known drug-binding sites on HSA, called Sudlow's site I and Sudlow's site II. To understand the strength of these interactions, they measured the association constants, which indicate how tightly the PFASFs bind to HSA.

Sudlow's Site I: PFOSF, PFHSF, and PFBSF showed association constants of 2.59 x 10⁻³ μM⁻¹, 4.65 x 10⁻³ μM⁻¹, and 2.85 x 10⁻³ μM⁻¹, respectively.
Sudlow's Site II: The association constants were 8.68 x 10⁻⁴ μM⁻¹, 3.43 x 10⁻² μM⁻¹, and 1.92 x 10⁻² μM⁻¹ for PFOSF, PFHSF, and PFBSF, respectively.

These values suggest that PFASFs can bind relatively tightly to HSA, potentially allowing them to be transported throughout the body via the bloodstream. The researchers also found that PFHSF and PFBSF can bind to additional sites on HSA, suggesting a more complex interaction than with PFOSF alone.

What Does This Mean for You?

This research highlights how PFASFs can interact with HSA, a major protein in your blood, potentially affecting how these chemicals are distributed throughout your body. This could have implications for where these chemicals accumulate and what health effects they might cause.

While more research is needed, this study adds to the growing body of evidence suggesting that PFAS chemicals can have far-reaching effects. Understanding how these chemicals interact with our bodies is a crucial step in assessing and mitigating their potential risks.

By demonstrating that PFASFs bind non-covalently to HSA, this research provides a theoretical basis for further toxicological and distribution studies of PFASFs in humans. This information is vital for developing strategies to reduce exposure and minimize the potential harm from these persistent environmental contaminants.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.toxlet.2018.11.001, Alternate LINK

Title: Perfluoroalkane Sulfonyl Fluorides Non-Covalently Bind To Human Serum Albumin At Sudlow’S Sites

Subject: Toxicology

Journal: Toxicology Letters

Publisher: Elsevier BV

Authors: Zhe Jin, Miao Chi, Quan He, Yuanjiang Pan, Cuirong Sun

Published: 2019-02-01

Everything You Need To Know

What are 'forever chemicals' or PFAS, and why are they a concern?

PFAS, or per- and polyfluoroalkyl substances, are man-made chemicals found in many products like non-stick cookware and firefighting foam. They're called 'forever chemicals' because they don't easily break down in the environment or in our bodies. While some, like PFOS, have been phased out, others are still used, raising health concerns.

What is human serum albumin (HSA), and how does it relate to the spread of PFAS in the body?

Human serum albumin (HSA) is the most abundant protein in blood and acts as a carrier for various molecules. Research indicates that PFAS, specifically perfluoroalkane sulfonyl fluorides (PFASFs), can bind to HSA. This binding could allow PFASFs to be transported throughout the body via the bloodstream, affecting where these chemicals accumulate and their potential health effects.

Which specific PFAS compounds were studied, and what method was used to observe their interaction with human serum albumin (HSA)?

The study focused on perfluoroalkane sulfonyl fluorides (PFASFs), specifically PFOSF (perfluorooctane sulfonyl fluoride), PFHSF (perfluorohexane sulfonyl fluoride), and PFBSF (perfluorobutane sulfonyl fluoride). Researchers used fluorescence spectroscopy to observe how these PFASFs interact with human serum albumin (HSA), identifying the binding sites on the HSA molecule.

Where do perfluoroalkane sulfonyl fluorides (PFASFs) bind on human serum albumin (HSA), and what does this binding affinity suggest?

Researchers discovered that perfluoroalkane sulfonyl fluorides (PFASFs) primarily bind to two well-known drug-binding sites on human serum albumin (HSA), named Sudlow's site I and Sudlow's site II. The association constants measured indicate how tightly each PFASF binds to these sites, suggesting they can be transported throughout the body. For example, PFHSF and PFBSF exhibit a more complex interaction than PFOSF alone by binding to additional sites on HSA.

What are the potential implications of perfluoroalkane sulfonyl fluorides (PFASFs) binding to human serum albumin (HSA) for human health?

The research highlights the interaction between perfluoroalkane sulfonyl fluorides (PFASFs) and human serum albumin (HSA). This interaction suggests that these 'forever chemicals' can be distributed throughout the body via the bloodstream. This could influence where these chemicals accumulate within the body and, consequently, what health effects they might have. Further research is needed to fully understand these long-term implications and potential mitigation strategies.