The application of batch processing LFIAs (lateral-flow immunoassays) has been very popular in the research and testing field and the diagnostic market. However, the limitations and test-to-test variability gave rise to high demand for a more quantitative process. This led to the development of an In-Line LFIA that makes use of quantitative dispensing methods. An automated system, the quantitative dispensing method is capable of producing higher test volumes as compared to the batch processing LFIAs. In addition, the incorporation of the in-line methods in the world of research has lowered down the scale-up risks and development costs. This article evaluates this latest trend in the diagnostic market.
The In-Line Process: An Upgrade in the Diagnostic Market
Often used as a substitute of the batch process, the in-line method has been developed to fulfill the higher demands of the diagnostic market. Due to its high-tolerance processes, it offers reduced CVs. Moreover, it successfully enables multitasking between the impregnation and dispensing applications. The following modules can be incorporated in the in-line process:
- Web Control - Dispensing consists of a payout reel that features web-speed control and tension, comprises of a web tracking methodology for locating the web edge in relation to the dispenser position, and then further aligning it on the take-up reel.
- Dip Tank - This module includes a reagent reservoir and a refill system. The reservoir impregnates a moving web. Powered by a reagent level sensor, the refill system retains a gradual and continuous flow of fluids into the tank. This ensures a consistent amount of fluid in the tank.
- Dry Tower -The main objective of a dry tower is to curtail the foot point of the composite machine with the help of a vertical web path.
- Lamination and Cutting. This feature allows the in-line process to accommodate the addition of other types of value added process modules. For instance, it is possible for a laminating module to laminate the webs (treated with reagents) with other materials.
- In-Line Slitting - The combination of a rotary blade system, reel feed system and various take-up reels, this module is generally used for slitting the wider webs into narrower formats.
- In-Line LaminationThe task of this in-line module is to first assemble the different pre-treated component layers, slit them to suitable widths and then re-rolling them into a laminating card or roll.
Impregnation Process vs. Quantitative Dispensing
- The In-line (quantitative dispensing) system is a fully automated and modular system based on individual application requirements. However, the batch process (impregnation process) required numerous human interventions. Thus, the introduction of in-line process in the diagnostic market minimizes the risk factor
- The in-line process offers more symmetry and control as compared to the batch process.
The advantages that the in-line system offers have led to growing acceptance of this research and testing option in the diagnostic market.