BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to passive wireless ionic sensors. More specifically, the present invention relates to modular cap-integrated ionic sensors for sample tube batches.

Background Art

Ionic sensing in real-time across a multitude of lab samples is a labor-intensive task, wherein the researcher may have to manually measure each sample container or, at a minimum, fabricate a measurement apparatus for each sample. It also exposes samples to varying environmental conditions with each measurement. For example, it has previously been found that varying oxygen levels can cause differences in gene expression. Oxygen content is a condition which could vary in local atmosphere due to heterotrophic microbial respiration, human respiration, or other reaction pathways, and should be controlled for in pH monitoring of cultures. Other applicable scenarios can be listed as, for example, water samples being monitored over time: exposure to CO2will cause the creation of carbonic acid and alter pH readings assumed to be the result of other factors. There are a variety of biological and environmental samples in which chemical monitoring should be performed in atmospheres where humidity, temperature, and gas content are controlled.

Ionic sensing in enclosed environments is currently possible but either costly, difficult to arrange into an apparatus, or still requires manual input. The most common device used is the glass style, dual junction, Ag/AgCl sensors for monitoring the pH of a solution; these feature low drift and high accuracy but take up considerable space and, if fitted individually to each sample container, would be prohibitively expensive. A researcher can choose to purchase these in bulk and fit them to a batch of samples to be monitored simultaneously; however, there are only a few real-time monitoring solutions available and most feature only a few input channels. Further, these systems are quite expensive.

BRIEF SUMMARY OF THE INVENTION

It is an objective of the present invention to provide systems, devices, and methods that allow for continuous, wireless ionic sensing, as specified in the independent claims. Embodiments of the invention are given in the dependent claims. Embodiments of the present invention can be freely combined with each other if they are not mutually exclusive.

The present invention features a reusable sample container cap with swappable sensors which can be screwed on to a standard sample tube and fitted to a base station monitoring an array of containers. One embodiment of this system is shown inFIG.1B, which shows a basic layout of this system and the cap-integrated receiver (RX) side. This device uses inductively coupled coils for power transmission and communication (by load modulation—LM), sampling an iridium oxide (IrOx) probe. An LM printed circuit board (PCB), with solenoid antenna, is fitted to the cap and interfaces with disposable IrOx/AgCl electrodes on polyimide substrates. There are several benefits of this design. First, electrodeposited IrOx probes are simple and inexpensive to produce as well as being high performance materials. Second, these caps can be designed to fit a variety of pre-existing tube designs of varying capacity (20 mL, 30 mL, 50 mL and 100 mL). Third, the passive wireless system reduces device complexity and cost, and the live/continuous data recording allows users to both keep their samples out of ambient environmental conditions and perform analysis in real time. Given the simplicity of both the transmitting and receiving sides, the system can easily be reconfigured to communicate continuously with large sets of samples or can include linear/rotary mechanical systems for rapid discrete measurements of that same sample set. The physical circuit arrangement can be easily rearranged to accommodate a variety of sensor materials and configurations such as similar planar probes of other material families, identical probes bearing other metal oxides, glassy dual junction probes, etc. The complete system also features instrumentation for modulated signal extraction, upload to a cloud database, and graphical-user-interface (GUI) access. It is believed that this device may yield significantly improved data collection in a myriad of lab sciences.

One of the unique and inventive technical features of the present invention is a cap with an integrated potentiometric chemical sensor and passive wireless transmitter. Without wishing to limit the invention to any theory or mechanism, it is believed that the technical feature of the present invention advantageously provides for wireless and continuous data collection from a number of chemical samples. Furthermore, the circuitry can be interchanged to monitor other ionic sensors. None of the presently known prior references or work has the unique inventive technical feature of the present invention.

The prior references teach away from the present invention. For example, most recent literature in wireless sensing makes use of digital schemes, such as Bluetooth (BT) communication; while robust and scalable in terms of channels, their additional complexity typically necessitates onboard energy storage (even Bluetooth Low Energy (BLE) systems), which adds further complexity and necessitates limits on the overall form factor which exceed those of a single analog LM application-specific integrated circuit (ASIC) and antenna. The base station still requires a power amplifier but the simpler analog-to-digital (ADC) circuitry is moved to the RX side, further increasing cost, complexity, and power requirements in the portion of the system which is to be mass produced (the cap); this is not to mention the additional BT or BLE circuitry which is now required at the base station, and the fact that BT/BLE communication must be cycled sequentially to sample from a batch of caps differs in no temporal way from sequential analog sampling. Therefore, digital communication schemes, which have become the norm, serve to further complicate the system in question and raise its cost while providing little benefit outside of added signal robustness. That being said, the present invention still allows for the addition of digital communication with minimal modification, if so desired.

A second example of prior literature teaching away from the present invention is that of single-point measurement systems, typically referred to as “system-on-chip” (SoC) or “lab-on-a-chip” (LoC). Many recent patents and academic literature focus on systems in which the sample is transported to, or drawn into, a system featuring a chemical sensor and onboard circuitry; however, there has been little focus on integration of those systems into convenient application-based physical configurations via form factor reduction (device simplicity) and low production costs (segmentation of reusable and disposable sections). To the first point: many designs attempt the digital communication scheme discussed above, if the SoC/LoC even communicates wirelessly. To the second: while disposable chemical sensors attached to reusable SoC/LoC's have been demonstrated, they are typically monolithic in terms of their sensor interface, communication hardware, and sample interface hardware; the design described herein is modular in the sense that sensing, communication, and antenna circuitry and physical sample interface hardware can all be easily separated and replaced or modified as necessary. Therefore, the prior art teaches away from this invention in that the current trend is to unify the components, rather than modularize them for various sensing duties.

Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.

