Quality Control of UCNP Conjugates: A Practical Guide
Producing a UCNP conjugate is one thing. Knowing that it will perform as intended is another.
When working with upconverting nanoparticles (UCNPs), knowing that the conjugation was successful is extremely important as potential changes in particle concentration and biomolecule functionality, or particle aggregation can affect downstream assay performance.
That is why quality control should be an integral part of a UCNP conjugation workflow.
To make this process easier, we have created a practical guide to quality control of UCNP conjugates, covering three fundamental questions:
- What is the concentration of your UCNP conjugate?
- Are the nanoparticles properly dispersed in the solution?
- Is the conjugated biomolecule still functional?
What should you test after UCNP conjugation?
A good quality-control workflow should tell you more than whether conjugation occurred. It should help establish whether the resulting UCNP conjugate is consistent, stable, and suitable for its intended application.
- UCNP concentration
Knowing the actual concentration of upconverting nanoparticles in your conjugate is important for reproducible experiments and assay development. Losses can occur during conjugation, purification, washing, and handling. Assuming that the final UCNP concentration is identical to the starting concentration can therefore introduce unwanted variation between experiments or batches. Our guide describes a practical approach for determining UCNP concentration so that subsequent experiments can be based on the material you actually have, not simply the amount you started with.
- Dispersion stability
Nanoparticle aggregation can have a major impact on UCNP conjugate performance. A conjugate that appears acceptable immediately after preparation may behave differently during storage or under assay conditions. Monitoring UCNP dispersion stability can help identify aggregation and other changes that could affect reproducibility, binding behavior, and analytical performance. The guide explains how to evaluate whether your UCNP conjugates remain properly dispersed.
- UCNP conjugate functionality
Physical stability is only part of the picture. After conjugating antibodies, proteins, or other biomolecules to UCNPs, it is important to verify that the biological component still performs its intended function.In other words: the presence of a biomolecule on the nanoparticle surface does not necessarily mean that the conjugate is functional.
The guide provides practical direction for confirming UCNP conjugate functionality and assessing whether the conjugated material is ready for downstream use.
Practical guidance backed by two decades of UCNP expertise
The guide was written by our UCNP expert Terhi Riuttamäki, who holds a PhD in upconverting nanoparticles and has spent more than 15 years at Uniogen advancing the Upcon upconverting nanoparticle technology and its applications.
Rather than providing a purely theoretical overview, the guide draws on hands-on experience with UCNPs and focuses on practical quality-control methods that researchers and assay developers can apply to their own conjugates. This guide explains how to address the most relevant quality control questions in your own laboratory using a single instrument and only small sample volumes. While more advanced and highly accurate analytical methods are available, the focus of this guide is on providing assay developers with practical approaches that are sufficient for routine UCNP conjugate characterization and quality control.
Whether you are developing a new UCNP-based assay, optimizing a conjugation protocol, troubleshooting inconsistent results, or establishing routine QC procedures, the guide provides a useful framework for evaluating your conjugates before moving forward.
Get the Practical Guide to Quality Control of UCNP Conjugates
Reliable UCNP-based assays start with well-characterized conjugates.
If you work with UCNP conjugation, upconversion nanoparticles, nanoparticle-based assays, or UCNP-based detection, contact us to get the guide to learn practical approaches for measuring UCNP concentration, evaluating dispersion stability, and confirming conjugate functionality. You can use the contact form below, or send an email to sales@uniogen.com.
The guide to quality control of UCNP conjugates was prepared by Terhi Riuttamäki, PhD, on behalf of Uniogen Oy.
Dr. Riuttamäki was among the first researchers at the University of Turku to focus on UCNPs. After completing her PhD on the topic, she has dedicated more than 15 years to advancing Uniogen’s Upcon® technology. She often describes the nanoparticles as “her first child,” reflecting her long-standing commitment to their development and application. Today, she works closely with customers and Uniogen’s technical teams to integrate Upcon® technology into various applications. Drawing on extensive experience in product development, technology transfer, and manufacturing scale-up, she helps customers achieve successful implementation and performance outcomes.
